1. Field of the Invention
The present invention relates to an organic thin-film device, and more particularly to an organic thin-film device which employs a Langmuir Blodgett (LB) film and has a small threshold value of the external potential.
2. Description of the Background Art
A. Aviram et al. of IBM have presented an idea of using molecules comprising tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF) which are linked with each other by several number of methylene chains, as a rectifier (Chemical Physics Letters, Vol. 29, No. 2, p.277). It, however, in itself is very difficult to synthesize such molecules themselves, and, even if they could by synthesized, it is difficult to orient the TCNQ and TTF in the state that no charge transfer complexes are formed.
Then, a method has been proposed in which donor molecules and acceptor molecules are made into separate solutions and the solutions are successively spread on a liquid surface to form a laminate film by stacking the different monomolecular films according to a Langmuir Blodgett process (hereinafter "LB process"), as disclosed in Japanese Patent Laid-Open Specification No. 62-65477. In recent years, techniques in which thin-films comprising organic molecules are formed by the LB process have undergone rapid developments, and this has led to increased research into organic thin film devices. These devices exhibit superior performance by controlling a charge transfer between donor molecules and acceptor molecules using external energy such as voltage and light beam. In these devices, however, a reasonably large external energy is required in order to obtain a desired performance, i.e., to normally operate these devices, and the devices have problems in their efficiency, operability, heat generation, durability, etc.